Abstract

Evolutionary theory provides the biological sciences, with a fundamental and powerful model to explain the emergence of cooperative behavior. A detailed explanation for the existence of cooperation between related individuals is provided by the theory of kin selection. However, one cannot explain examples of apparent altruism through kin selection, because in these cases unrelated individuals interact. In my dissertation I have tested empirically new models and predictions of how cooperation between unrelated humans can be established. This research is especially important because we interact in a close net of relationships, where cooperation between unrelated individuals plays one of the main roles. Modern human societies are impossible to imagine without cooperation between unrelated individuals. By identifying the circumstances under which cooperation is stable between unrelated individuals, we would be provided with intellectual tools to positively influence the deciding factors by alternating the circumstances accordingly.